I searched but didn't find any post for a diy rotor/disc change. Is it a difficult job? I saw the brake pad change thread on the 335 and it looks fairly simple. Is it just 2 bolts holding the caliper to rotor? We're talking E90 here. I'm looking to order my parts from here: http://www.autopartsway.com/autopart...1660~241660~22
Thanks

It is really easy and yes only two bolts hold the capilper to the rotor.I belive they are 18mm bolts but the bolts could be 19mm. The rotor is self is held on to the hub by one 6mm hex bolt, be carefull not to strip the 6mm hex bolt because you will be in trouble. I recomend to replace them every time you replace rotors. The rotors might be stuck to hub because of rust but a few blows with a mallet should remove the rotors. Clean off the Hub and aply anti-seize to preven rust and the rotors from getting stuck.

That should be it, just re assemble everything back and you will be done.

rotors are mainly held on by the caliper and the lug nuts. It is very easy to uninstall and install new rotors. just follow the same steps to change your pads but take the caliper and bracket all the way off.

So just a tip here. The flat-head bolt that holds the rotor to the hub is very easy to strip the Allen-head hex hole. IIRC it takes a 5MM Allen wrench. I found over the many years of removing BMW rotors that using an L-shaped Allen Key (wrench), which most people have in their tool box, makes it easy to strip the bolt head. I suggest getting the proper-sized Allen socket and a T-wrench to remove the bolt. Also, since they cost 30 cents, buy 4 extra the next time you replace the rotors, so the bolts are fresh. I believe that of the many heat cycles the bolts go through softens the metal and allows them to strip easily. Also, use antiseize on them when re-installing. Better yet, if you have an air compressor, one of the best air tools to buy is a “Butterfly” impact wrench. The Butterfly wrench is ideal for removing the rotor bolts.

The short stubby one is really good for getting at the guide bolts.
The variable size length ratchets let you get the most turn with a neck that bends so you can get at the caliper bolt. The ones in the rear of my E90 330xi were challenging to get to with little rotation room.

Here’s my experience on changing Pads & Rotors. Hope this could help others.

• Put car on 4 jack stands (see separate DIY on how to properly jack your car up on to stands). Make sure to loosen your wheel lugs before the car is up.
• Open the brake reservoir cap (less pressure when sitting the pistons back).
• (Optional) Suck out some brake fluid from the brake reservoir with a turkey blaster….will flush brake fluid after the brake job since the car is already on jack stands with wheels off (Separate DIY).
• Take off wheel and first thing you want to do is spray some PB Blaster (lubricant) to the wheel hub where the rotor sits on and also spray some to the two bolts that holds the caliper bracket. This will make things easier later.
• Loosen the 6mm hex from the rotor, but keep the bolt on so that the rotor stays in place. I slide a hex key into the edge of the rotor where heat vents and against the caliper so that the rotor will not move when you’re trying to loosen the 6mm hex bolt (This will prevent the rotor from turning when you’re trying to turn the hex bolt).
• Take off the clip from the caliper.
• Take off sliding pin plastic covers and use 7mm hex socket to remove the caliper pins. An extension bar might be needed in some tight areas behind the rotor.
• Slide the caliper off, I had to use a screwdriver to pry the pads against both sides of the rotor (Warning! If you’re not replacing your rotors, be careful not to damage your rotors). Do not pry on the piston boot.
• Ones the caliper is off, I highly recommend hanging the caliper with ropes/hooks etc. You don’t want to put stress on the brake lines and this will also allow you to have more space to work on the brackets. You want to hang it as high as you can and away from the bracket without stressing the brake lines.
• The caliper brackets = the fun part: Do not use the Metric size; instead use the SAE size for a better snug on these bolts. I believe 18mm for the front and 16mm for the rear so find the SAE equivalent for those sizes. You will only have enough room to remove these bolts from the caliper side. This is why you want to hang the caliper to give yourself plenty of space. Be careful not to strip the bolts (use more PB Blaster on the bolts if needed).
• Remove the 6mm hex from the rotor, then remove the rotor from the hub…hammer the surface of the rotor and be careful not to hit the hub (use more PB Blaster if needed).
• Remove the old pads from the caliper and sit the piston back (I used a C clamp). Remember that the reservoir cap was left open; you shouldn’t have to use too much force when sitting the piston back.
• Now just clean the necessary parts/areas (use brake cleaners and sandpapers).
• Same process for other 3 wheels/brakes. Also replace the 2 brake sensors and install everything back (see below for more details)
• Remember to close the brake reservoir cap when you’re done.

Other notes:
• Putting back on the bracket bolts; be very careful when you torque these bolts. The front bolts are twice as big as the rears. I made the mistake of over torque one of the rear bolts and it broke. You want to properly torque them to the steering knuckle but don’t over torque. A short torque wrench is ideal for the rear (no more than a foot long). Here are the specs: Front bolt = 110nm/81ft lbs Rear bolt = 65nm/48ft lbs
• Anti-seize the bracket area where the pads sit on (the area where the edge of the pads sit/move on).
• Anti-seize the hub area.
• Use brake grease (not anti-seize) on the sliding pins.
• Use brake quiet behind the pads.
• Don’t forget to put the plastic dust covers back on for the sliding pins.
• There will be a lot of brake dust that you’ll be breathing in, use a mask unless you want your lungs to look like your wheels lol.
• If this is your first attempt, give yourself plenty of time to do this job. Don’t expect to finish in 3-4 hours; it could take 6+ hours…Good Luck!

Anyone know if it's ok to resurface BMW rotors? I put new EBC ceramic RED brake pads onto my existing rotors without resurfacing them (I also got the spray on disc brake quieter) but they squeal like crazy when I'm braking at slow speed after they've warmed up a little. The car has 55k miles on them and I believe this is the first brake change. The inner and outer edges are pretty high and then sink in a bit where the main pads hit the rotors so I'm thinking that's what's causing the squeal. The EBC Red brakes have an anti-squeal shim on them so I'm assuming the squeal is more coming from the the uneven rotor surface or edges. So my question is...is it too late to try resurfacing the rotors since I've put about 100 miles on the brake pads? (and does BMW even sanction resurfacing rotors or are they simply 1-time use?) OR should I just paste on some anti-brake squeal on the backs of the pads? HELP! The squeal is killing me!!!

Anyone know if it's ok to resurface BMW rotors? I put new EBC ceramic RED brake pads onto my existing rotors without resurfacing them (I also got the spray on disc brake quieter) but they squeal like crazy when I'm braking at slow speed after they've warmed up a little. The car has 55k miles on them and I believe this is the first brake change. The inner and outer edges are pretty high and then sink in a bit where the main pads hit the rotors so I'm thinking that's what's causing the squeal. The EBC Red brakes have an anti-squeal shim on them so I'm assuming the squeal is more coming from the the uneven rotor surface or edges. So my question is...is it too late to try resurfacing the rotors since I've put about 100 miles on the brake pads? (and does BMW even sanction resurfacing rotors or are they simply 1-time use?) OR should I just paste on some anti-brake squeal on the backs of the pads? HELP! The squeal is killing me!!!

This. Get the stuff BMW uses, should be under $1/packet at your dealer. It's worked well for me.

No reason why your rotors can't be resurfaced. Just make sure thickness is within spec before you do so (check Bentley manual or ask your dealer for service info).